Ed, have you actually called a dealer rather than just looking up on line? I have had a lot of problems with parts saying not available when I looked them up on websites, but were still available. Sometimes the part number had changed, sometimes there was a difference in the way the number was entered (spaces, hyphens, etc.).

Rubber hardness is measured by durometer, the higher the number, the harder the rubber. Rubber changes durometer somewhat as it ages, thus a used part might not have the same properties as new. If scarcity of these parts appears to be near, it would be very useful if the person finding a new one would take it to a commercial/industrial rubber supplier for identification of the durometer and other characteristics. Such suppliers can get equivalent material and cut it to any shape/size required. The specifications would be most welcome for my records.